Currently, in the field of regenerative medicine, studies in which stem cells collected from a subject are caused to proliferate or differentiate ex vivo, and are thereafter transplanted into a subject, thereby promoting regeneration of tissue of the subject have been carried out. Stem cells are multipotent and can differentiate into a variety of tissues and organs, and they have been attracting attention as cells which are key to regenerative medicine.
It has been known that in ex vivo cultural proliferation of stem cells, addition of a serum to the medium is effective. However, when human therapies are targeted, use of a serum derived from an animal other than from the human body should be avoided in light of possible problems of safety. Therefore, use of a serum prepared from blood which is derived from a human, in particular, which was collected from the same subject has been desired. In addition, culture of stem cells in the field of regenerative medicine requires relatively larger amounts of serum in comparison with blood tests.
As a method of preparing such a serum, a method in which a blood collection tube is used that contains a blood coagulation accelerating substance, such as glass powder is disclosed in JP-A No. 2000-000228.